Raman scattering spectra of ceramics, films, and superlattices of ferroelectric perovskites: A review

Raman investigations of the crystal lattice dynamics in classical ferroelectric perovskites SrTiO₃, PbTiO₃, and BaTiO₃ have been analyzed. The specific features revealed in the behavior of soft modes during the phase transitions occurring in ceramics and powders of these compounds, as well as in several related solid solutions, have been described. Particular attention has been paid to the investigations of ferroelectric thin films and superlattices in which the sequences of structural distortions can be radically different from those known for the initial bulk materials.